This invention relates to an exercising device.
Exercising devices using frictional resistance against the pull of cables are known in the prior art. For example, devices of this general type are found in U.S. Pat. Nos. 3,610,617; 3,690,654; and 3,764,132, all to Hepburn.
In U.S. Pat. No. 3,610,617, the two cables are each connected to a pulley and each pulley is mounted on a separate shaft. The frictional force on the shafts is achieved by tightening leather strips against the shaft. There is a knob connected to a bolt which threadedly engages a lower wooden block. By turning the knob, the lower block is tightened against an upper wooden block. The leather strips are located between the blocks and the shafts. This arrangement has certain disadvantages. For example a considerable force must be exerted on the knob for higher resistances against the pulling of the cables. A scale is provided to show the position of the knob and this is supposed to represent the upwards force exerted on the cables. However, the scale may not be accurate since the friction between the leather strips and the shafts varies as the leather strips compress or wear and varies with the lubrication between the leather and the shaft.
The device shown in U.S. Pat. No. 3,690,654 is similar to the device disclosed in the patent discussed above except that the cables are wound on the pulleys so as to alternately rotate the shaft in opposite directions.
In U.S. Pat. No. 3,764,132, a knob at one end of the housing of the device urges a pair of brake shoes against the shaft through an arrangement of wedges.